The launch of a joint US-Indian radar spacecraft is expected to be postponed to the latter part of this year due to ongoing adjustments necessary for its extensive retractable antenna.
According to an official statement issued by the National Aeronautics and Space Administration (NASA), USA, on March 22, the launch date for the NASA-ISRO Synthetic Aperture Radar (NISAR) mission would be rescheduled by end-April.
Recently, S Somanath, chairman of the Indian Space Research Organisation (ISRO) had stated that the NISAR launch would be postponed from the first quarter of the year. However, he did not provide specifics on the reason for the delay, except saying that it was unrelated to the rocket, GSLV Mark 2, which would be used for the launch. Somanath stated that NISAR was still being tested and there was the possibility of a delay in its launch. The launch, he said, was expected to occur in the second half of the year.
As reported previously, NASA officials had initially planned for the mission to take place during the spring season, with an estimated launch date at the end of March. However, the rescheduling decision has been made to ensure the protection of the spacecraft’s radar antenna reflector, a 12-metre (approximately 39-foot) antenna that needs to be safeguarded from extreme temperatures while it is in its folded state.
To address this issue, NASA plans to apply a specialized coating to the antenna. “This coating will improve the reflector’s ability to bounce off sunlight, thereby preventing the antenna from encountering excessive heat. According to an announcement by NASA, extensive testing and analyses indicate that the reflector on the spacecraft could be subjected to higher temperatures than originally anticipated when folded in-flight,” explains Girish Linganna, Bengaluru based aerospace and defence analyst.
According to information in the public domain, the reflector on the NISAR satellite is being shipped back to the US for an additional ‘special coating’, as the space agencies plan a new launch window for the earth observation satellite.
Why?
“Because, the special coating will reduce the temperature as it will reflect more of the solar radiation away from the reflector’s hardware, according to NASA,” Linganna adds.
For this purpose, the reflector, together with the rest of the NISAR spacecraft, is being shipped from the satellite assembly site in Bengaluru’s UR Rao Satellite Centre to a facility in California. This selected, specialized facility possesses the requisite amount of expertise and resources to effectively carry out the coating application procedure.
Significant Space Cooperation Milestone
NISAR marks a significant milestone as it is the inaugural joint Earth science spacecraft collaboration between NASA and ISRO. This partnership is one of the most substantial alliances between the two agencies, with NASA investing over US$1 billion solely in the mission’s formulation and development. The L-band radar and engineering payload will come from NASA, while ISRO will provide the S-band payload, spacecraft bus and launch vehicle.
NISAR will be the pioneering satellite mission to gather radar data in two distinct microwave frequency ranges:
L-band (1-2 GHz), which is widely utilized for satellite communication and remote-sensing applications, and
S-band (2-4 GHz), which is commonly employed for satellite communication and weather monitoring purposes.
According to Linganna, “The Synthetic Aperture Radar (SAR) is an innovative, remote-sensing technique that employs radar systems rather than traditional optical sensors to capture detailed images of Earth’s surface. This advanced technology has the ability to penetrate through clouds and dense vegetation, enabling the generation of precise and reliable data.”
Financial Express Online has reported previously, the NISAR mission aims at capturing comprehensive images of Earth’s land and ice masses on a regular basis. The spacecraft will be able to map the entire Earth every 12 days. The resulting data is anticipated to be promptly accessible, with a turnaround time of a few days after observation and even quicker in emergency situations, typically within a matter of hours.
What NASA, ISRO Wish to Achieve?
Disaster mapping is a significant aspect of the NISAR mission. By utilizing pre-disaster images, it seeks to enhance our understanding of disasters and aid in the development of effective policies for future events. Additionally, the advantage of satellite observations being unaffected by weather conditions allows for timely and credible information to be relayed during rescue operations and for estimating losses.
Forest habitats play a crucial role in our ecosystem, serving as sources of timber, fuel and various products. They also act as carbon sinks, helping reduce excess carbon in the atmosphere, while simultaneously purifying air and water resources. Additionally, forests provide habitats for numerous flora and fauna species. NISAR’s primary objective is to monitor, and assess, global forest resources—including their extent and quality, in order to facilitate sustainable development and effective management practices
Agriculture and food security are critical concerns and SAR imaging can play a pivotal role in addressing them. By capturing detailed images of crop rotation, growth and harvest, SAR technology can streamline agricultural planning and optimize output. Moreover, it enables the monitoring of crop health, allowing for early detection of issues that may impact food production. This information can contribute to enhancing agricultural practices and ensuring food security.
The NISAR project was allocated a substantial budget of USD 1.5 billion, equivalent to approximately Rs 12,505 crore in Indian currency around mid-2023. This makes it the costliest Earth-imaging satellite project globally. However, the overall cost may escalate due to the inclusion of additional coatings and other modifications that may be deemed necessary prior to launch.